I just committed the attached test case as obvious.
Added test case for a PR which has been fixed in the meantime. gcc/testsuite/ChangeLog: PR tree-optimization/50439 * gfortran.dg/loop_interchange_2.f: New test.
C { dg-do compile } C { dg-options "-std=legacy -O3 -floop-interchange" } C PR 50439 - this used to hang. Test case by Pat Haugen. subroutine comnul C----------------------------------------------------------------------- implicit real*8 (a-h,o-z) parameter(zero=0.0d0,half=0.5d0,one=1.0d0) common/secom/rtc(9,18,10,5),rts(9,18,10,5) save C----------------------------------------------------------------------- do 110 i1=1,9 do 110 i2=1,18 do 110 i3=1,10 do 110 i4=1,5 rtc(i1,i2,i3,i4)=zero rts(i1,i2,i3,i4)=zero 110 continue return end